Fan housing for a fan for supplying a fuel/oxidizer mixture to a burner, insert and supply device therefor

ABSTRACT

Fan housing for a fan for supplying a fuel/oxidizer mixture to a burner, comprising: a supply opening ( 22 ); a fluid supply space ( 26 ) debouching at the supply opening; a first supply means ( 28 ) for supplying a fluid-like fuel; a second supply means ( 52 ) for supplying an oxidizing fluid; wherein the fluid supply space comprises mixing means ( 50 ) for mixing the fluid-like fuel with the oxidizing fluid; and wherein the supply opening lies at an angle relative to the supply direction of the fluid in the fluid supply space.

The present invention relates to a fan housing for a fan for supplying a fuel/oxidizer mixture to a burner.

The invention further relates to an insert for such a fan housing.

The present invention also relates to a supply device for such a fan housing.

The present invention also relates to a heating appliance comprising such a fan housing.

The present invention also relates to a hot water appliance comprising such a fan housing.

The present invention also relates to a combi-boiler comprising such a fan housing.

The invention also relates to a method for supplying a fluid-like fuel with an oxidizing fluid to a fan.

Burners as applied in the prior art produce noise, this noise production being determined to a significant extent by the so-called thermo-acoustic behaviour. The thermo-acoustic behaviour is influenced not only by the burner itself but also by elements upstream and, to lesser extent, downstream of the burner. One of the elements affecting the thermal-acoustic behaviour is a fan which forces the fuel/air mixture through the burner.

The object of the present invention is to provide a heating appliance with an improved thermo-acoustic behaviour compared to the prior art.

The present invention provides for this purpose a fan housing for a fan for supplying a fuel/oxidizer mixture to a burner, comprising: a supply opening; a fluid supply space debouching at the supply opening; a first supply means for supplying a fluid-like fuel; a second supply means for supplying an oxidizing fluid; wherein the fluid supply space comprises mixing means for mixing the fluid-like fuel with the oxidizing fluid; and wherein the supply opening lies at an angle relative to the supply direction of the fluid in the fluid supply space.

In a preferred embodiment the fuel comprises natural gas and the oxidizing fluid comprises air. In an alternative embodiment the fuel comprises methane, propane and/or butane.

Measurements by applicant have shown that when the fuel/oxidizer mixture undergoes a considerable deflection in the flow direction before the mixture moves through the blade space in the fan, the thermo-acoustic behaviour of the burner is positively affected in the sense that the noise production decreases.

By providing this fan housing a heating appliance with an improved thermo-acoustic behaviour compared to prior art heating appliances is provided by applying the fan housing in a heating appliance.

In a preferred embodiment a fan housing is provided wherein the mixing means comprise a venturi. Due to the venturi an underpressure is created close to the venturi and downstream of the venturi, whereby the oxidizing fluid is drawn out of the second supply means and mixes with the fuel. An additional advantage is that the venturi and the fan housing are now integrated, whereby a more compact assembly is obtained. In prior art heating appliances the fan housing and the venturi are in contrast embodied as separate components.

In a further preferred embodiment the present invention provides a fan housing wherein the supply opening is disposed transversely of the supply direction of the fluid in the fluid supply space. Measurements by applicant have shown that the transverse placing of the supply opening has a particularly favourable effect on the thermo-acoustic behaviour of the burner.

In yet a further advantageous embodiment a fan housing is provided wherein the second supply means is arranged in the first supply means and lies in the flow direction of the first supply means, and which second supply means debouches in the first supply means, and wherein the first supply means comprises a narrowing close to the mouth of the second supply means. The narrowing close to the mouth of the second supply means forms the venturi. Because the venturi is arranged on the second supply means, which is in turn arranged in the first supply means, and this assembly is formed integrally with the fan housing, a particularly compact construction is obtained. A heating appliance is hereby obtained which not only has a more favourable thermo-acoustic behaviour than in the prior art but is also more compact.

In a very advantageous embodiment the invention provides a fan housing wherein at or close to the mouth of the second supply means an obstruction extends over a part of the peripheral wall of the second supply means in downstream direction to a position some distance from the mouth in order to impede, close to the mouth of the second supply means, a fluid flow transversely of the main flow direction in the first supply means.

Measurements by applicant have once again shown that arranging this obstruction has a positive effect on the thermo-acoustic behaviour of a heating appliance comprising such a fan housing. Particularly when a stagnation occurs downstream of the fan, for instance in the discharge of flue gases, the obstruction makes a positive contribution toward the thermo-acoustic behaviour. When such a stagnation occurs a circulating underpressure results at the position of the supply opening of the fan housing. The obstruction impedes the circulating fluid flow and causes a local pressure increase at the position of the mouth of the second supply means, whereby the gas supply stops. The result is a more favourable thermo-acoustic behaviour than is the case in the prior art.

The positive effect of the obstruction on the thermo-acoustic behaviour is irrespective of the fact that the supply opening of the fan housing lies at an angle relative to the supply direction of the fluid in the fluid supply space. Both the obstruction and the angle each have a favourable effect on the thereto-acoustic behaviour and can be implemented independently of each other.

In a preferred embodiment the invention provides a fan housing wherein the protruding obstruction is an extension of the wall of the second supply means. The obstruction can in this way be formed in simple manner.

In an advantageous embodiment the present invention provides a fan housing wherein the second supply means and the mixing means are formed from an insert which can be placed in the fluid supply space. By embodying the second supply means and the mixing means as an insert an assembly is obtained which is compact compared to the prior art, and the option is also provided of modifying the fan housing in simple manner to the design capacity for the heating appliance by only varying the insert and manufacturing the rest of the fan housing in a single embodiment for different types of heating appliance of differing capacity.

The present invention also provides such an insert.

In an alternative embodiment the invention provides a. supply device for supplying fluid to a fan housing, comprising a closing part for closing a supply side of a fan housing; a fluid supply space for supplying a fluid, wherein the fluid supply space debouches on the fan side of the closing part by means of a supply opening; a first supply means for supplying fluid-like fuel; a second supply means for supplying an oxidizing fluid; wherein the fluid supply space comprises mixing means for mixing the fluid-like fuel with the oxidizing fluid; and wherein the supply opening lies at an angle relative to the supply direction of the fluid in the fluid supply space.

As an alternative to a fan housing in which the mixture of the fluid-like fuel and the oxidizing fluid are carried at an angle into the fan housing, the present invention provides an embodiment in which only a supply device is provided, which can be arranged on the supply side of a fan housing. In a specific embodiment the supply device is embodied as a cover of the fan housing.

In an embodiment the present invention further provides a heating appliance comprising such a fan housing or a fan housing comprising such a supply device.

In a further embodiment the invention also provides a hot water appliance comprising such a fan housing or a fan housing comprising such a supply device.

In a further embodiment the present invention also provides a combi-boiler for heating tap water and central heating water, the combi-boiler comprising such a fan housing or a fan housing comprising such a supply device.

According to another aspect according to the invention, a method is provided for supplying a fluid-like fuel with an oxidizing fluid to a fan, comprising the steps of: guiding the fluid-like fuel through a venturi; providing the oxidizing fluid in or close to the venturi, whereby the oxidizing fluid is drawn in by the venturi effect and mixes with the fluid-like fuel; supplying the mixture of the fuel and the oxidizing fluid at an angle to a fan, which fan blows the mixture into a burner space.

Further embodiments and advantages of the present invention are discussed hereinbelow with reference to figures, in which:

FIG. 1A shows a partially cut-away view of a fan housing with a supply device according to the present invention arranged thereon;

FIG. 1B shows an exploded view of the fan housing of FIG. 1B;

FIG. 1C shows the rear side relative to FIGS. 1A and 1B of the fan housing of FIGS. 1A and 1B;

FIG. 2 shows a front view of a supply device according to the present invention;

FIG. 3 shows an axonometric view of the supply device of FIG. 2; and

FIG. 4 shows a second axonometric view of the supply device of FIG. 2.

A fan housing 10 (FIG. 1) is provided with a supply device 20 according to the present invention. Supply device 20 is embodied as a cover arranged on the supply side of fan housing 10. Fan housing 10 comprises a main body 30 and a discharge conduit 42 for guiding a gas/air mixture to the burner.

The natural gas is supplied via a supply conduit 28, in which is placed the insert 50 comprising a venturi 54. Venturi 54 causes an underpressure downstream of the venturi in the natural gas supply conduit 28. Owing to this underpressure air is drawn in from air supply conduit 52, whereby a mixing of the natural gas and the air occurs in fluid supply space 26, a part of the outer wall 24 of which is cut away in FIG. 1A. Recessed into cover 20 is a supply opening 22 through which the natural gas/air mixture flows into fan housing 10. Rotation of the fan creates an underpressure at the position of supply opening 22, which underpressure causes the natural gas/air flow out of the fluid supply space into fan housing 10. At the moment that the natural gas/air mixture flows via supply opening 22 into fan housing 10 the gas flow is deflected to a considerable extent by the arrangement of supply opening 22 transversely of the main flow direction in fluid supply space 26. An overpressure is created at supply conduit 42, whereby the natural gas/air mixture flows via discharge conduit 42 into the burner.

FIG. 2 shows a fan housing cover similar to that of FIG. 1. In this figure the wall 24 of the fluid supply space is omitted in order to illustrate the underlying components. On a part of the periphery of the mouth of air supply conduit 52 the insert 50 is provided with an extension 56 of the wall of air supply conduit 52. Because air supply conduit 52 does not extend further at the position of extension 56, mixing of natural gas and air is possible at this position. A transverse flow of the natural gas/air mixture is however prevented here by extension 56. This is found to have a favourable effect on the thermo-acoustic behaviour of the burner.

FIG. 3 again shows fan housing cover 20 of FIG. 2, although here from a different angle, wherein a part of cover 20 and of fluid supply space 26 is cut away.

FIG. 4 once again shows fan housing cover 20 of FIG. 2, although here from yet another angle, wherein the same part of cover 20 and of fluid supply space 26 is cut away as in FIG. 3.

The shown and described embodiments are only included for the purpose of illustrating the principle of the invention and to show or describe several advantageous embodiments. The invention is not limited to the shown and described embodiments. It will be apparent to the skilled person that many modifications of the shown embodiments are possible within the invention. It is thus possible without problem to combine the different shown or described embodiments and so once again obtain embodiments according to the invention. The protection sought is therefore not defined by the shown and described embodiments but by the following claims. 

1.-14. (canceled)
 15. A housing for a fan for supplying a fuel/oxidizer mixture to a burner, comprising: a housing structure having a supply opening therein; a fluid supply space attached to the housing and providing a fluid connection to the supply opening; a first supply means of a fluid-like fuel in fluid connection with the fluid supply space; a second supply means of an oxidizing fluid in fluid connection with the fluid supply space; wherein the fluid supply space comprises a mixing means for mixing the fluid-like fuel with the oxidizing fluid; and wherein the supply opening is positioned in the housing structure at an angle relative to the supply direction of the fluid in the fluid supply space.
 16. The housing as claimed in claim 15, wherein the mixing means is configured in a manner so as to provide a venturi effect.
 17. The housing as claimed in claim 15, wherein the supply opening is disposed transversely of the supply direction of the fluid in the fluid supply space.
 18. The housing as claimed in claim 17, wherein the second supply means is arranged in the first supply means and is positioned in a flow direction of the first supply means, and wherein the second supply means is aligned with the first supply means, and wherein the first supply means comprises a narrowing close to a mouth of the second supply means.
 19. The housing as claimed in claim 18, wherein at the mouth of the second supply means an obstruction extends over a part of a peripheral wall of the second supply means, the obstruction being configured to extend in a downstream direction of flow from the second supply means to the supply opening, the obstruction configured in a manner so as to impede fluid flow transversely of the first supply means and second supply means.
 20. The housing as claimed in claim 19, wherein the obstruction is an extension of a wall of the second supply means.
 21. The housing as claimed in claim 15, wherein the second supply means and the mixing means are formed from an insert placed in the fluid supply space.
 22. A supply device for supplying fluid to a fan housing, comprising a closing part which covers a supply side of a fan housing; a fluid supply space attached to the closing part and providing a fluid connection to a supply opening; a first supply means for supplying a fluid-like fuel; a second supply means for supplying an oxidizing fluid; wherein the fluid supply space comprises a mixing means for mixing the fluid-like fuel with the oxidizing fluid; and wherein the supply opening is positioned at an angle relative to the supply direction of the fluid in the fluid supply space.
 23. A heating appliance comprising a housing as claimed in claim
 15. 24. A hot water appliance comprising a housing as claimed in claim
 15. 25. A combi-boiler for heating tap water and central heating water, the combi-boiler comprising a fan housing as claimed in claim
 15. 26. A method of supplying a fluid-like fuel with an oxidizing fluid to a fan, comprising the steps of: guiding the fluid-like fuel through a venturi; providing the oxidizing fluid flow in proximity to the venturi, whereby the oxidizing fluid is drawn in by the venturi effect and mixed with the fluid-like fuel; supplying the mixture of the fuel and the oxidizing fluid at an angle to a fan, which fan blows the mixture into a burner space.
 27. A housing for a fan for supplying a fuel/oxidizer mixture to a burner, comprising: a housing structure having a supply opening therein; a fluid supply space attached to the housing and providing a fluid connection to the supply opening; a first supply means of a fluid-like fuel in fluid connection with the fluid supply space; a second supply means of an oxidizing fluid in fluid connection with the fluid supply space; wherein the fluid supply space comprises a mixing means for mixing the fluid-like fuel with the oxidizing fluid; and wherein at a mouth of the second supply means an obstruction extends over a part of a peripheral wall of the second supply means, the obstruction being configured to extend in a downstream direction of flow from the second supply means to the supply opening, the obstruction configured in a manner so as to impede fluid flow transversely of the first supply means and second supply means.
 28. A set of housings as claimed in claim 21, for use in heating appliances of different types and of different capacities, wherein each housing is identical but has a different insert forming the second supply means and the mixing means. 